src/cris/ffi.c

/* -----------------------------------------------------------------------
   ffi.c - Copyright (c) 1998 Cygnus Solutions
           Copyright (c) 2004 Simon Posnjak
	   Copyright (c) 2005 Axis Communications AB

   CRIS Foreign Function Interface

   Permission is hereby granted, free of charge, to any person obtaining
   a copy of this software and associated documentation files (the
   ``Software''), to deal in the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:

   The above copyright notice and this permission notice shall be included
   in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   IN NO EVENT SHALL SIMON POSNJAK BE LIABLE FOR ANY CLAIM, DAMAGES OR
   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   OTHER DEALINGS IN THE SOFTWARE.
   ----------------------------------------------------------------------- */

#include <ffi.h>
#include <ffi_common.h>

#define STACK_ARG_SIZE(x) ALIGN(x, FFI_SIZEOF_ARG)

static ffi_status
initialize_aggregate_packed_struct (ffi_type * arg)
{
  ffi_type **ptr;

  FFI_ASSERT (arg != NULL);

  FFI_ASSERT (arg->elements != NULL);
  FFI_ASSERT (arg->size == 0);
  FFI_ASSERT (arg->alignment == 0);

  ptr = &(arg->elements[0]);

  while ((*ptr) != NULL)
    {
      if (((*ptr)->size == 0)
	  && (initialize_aggregate_packed_struct ((*ptr)) != FFI_OK))
	return FFI_BAD_TYPEDEF;

      FFI_ASSERT (ffi_type_test ((*ptr)));

      arg->size += (*ptr)->size;

      arg->alignment = (arg->alignment > (*ptr)->alignment) ?
	arg->alignment : (*ptr)->alignment;

      ptr++;
    }

  if (arg->size == 0)
    return FFI_BAD_TYPEDEF;
  else
    return FFI_OK;
}

int
ffi_prep_args (char *stack, extended_cif * ecif)
{
  unsigned int i;
  unsigned int struct_count = 0;
  void **p_argv;
  char *argp;
  ffi_type **p_arg;

  argp = stack;

  p_argv = ecif->avalue;

  for (i = ecif->cif->nargs, p_arg = ecif->cif->arg_types;
       (i != 0); i--, p_arg++)
    {
      size_t z;

      switch ((*p_arg)->type)
	{
	case FFI_TYPE_STRUCT:
	  {
	    z = (*p_arg)->size;
	    if (z <= 4)
	      {
		memcpy (argp, *p_argv, z);
		z = 4;
	      }
	    else if (z <= 8)
	      {
		memcpy (argp, *p_argv, z);
		z = 8;
	      }
	    else
	      {
		unsigned int uiLocOnStack;
		z = sizeof (void *);
		uiLocOnStack = 4 * ecif->cif->nargs + struct_count;
		struct_count = struct_count + (*p_arg)->size;
		*(unsigned int *) argp =
		  (unsigned int) (UINT32 *) (stack + uiLocOnStack);
		memcpy ((stack + uiLocOnStack), *p_argv, (*p_arg)->size);
	      }
	    break;
	  }
	default:
	  z = (*p_arg)->size;
	  if (z < sizeof (int))
	    {
	      switch ((*p_arg)->type)
		{
		case FFI_TYPE_SINT8:
		  *(signed int *) argp = (signed int) *(SINT8 *) (*p_argv);
		  break;

		case FFI_TYPE_UINT8:
		  *(unsigned int *) argp =
		    (unsigned int) *(UINT8 *) (*p_argv);
		  break;

		case FFI_TYPE_SINT16:
		  *(signed int *) argp = (signed int) *(SINT16 *) (*p_argv);
		  break;

		case FFI_TYPE_UINT16:
		  *(unsigned int *) argp =
		    (unsigned int) *(UINT16 *) (*p_argv);
		  break;

		default:
		  FFI_ASSERT (0);
		}
	      z = sizeof (int);
	    }
	  else if (z == sizeof (int))
	    *(unsigned int *) argp = (unsigned int) *(UINT32 *) (*p_argv);
	  else
	    memcpy (argp, *p_argv, z);
	  break;
	}
      p_argv++;
      argp += z;
    }

  return (struct_count);
}

ffi_status
ffi_prep_cif (ffi_cif * cif,
	      ffi_abi abi, unsigned int nargs,
	      ffi_type * rtype, ffi_type ** atypes)
{
  unsigned bytes = 0;
  unsigned int i;
  ffi_type **ptr;

  FFI_ASSERT (cif != NULL);
  FFI_ASSERT ((abi > FFI_FIRST_ABI) && (abi <= FFI_DEFAULT_ABI));

  cif->abi = abi;
  cif->arg_types = atypes;
  cif->nargs = nargs;
  cif->rtype = rtype;

  cif->flags = 0;

  if ((cif->rtype->size == 0)
      && (initialize_aggregate_packed_struct (cif->rtype) != FFI_OK))
    return FFI_BAD_TYPEDEF;

  FFI_ASSERT_VALID_TYPE (cif->rtype);

  for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
    {
      if (((*ptr)->size == 0)
	  && (initialize_aggregate_packed_struct ((*ptr)) != FFI_OK))
	return FFI_BAD_TYPEDEF;

      FFI_ASSERT_VALID_TYPE (*ptr);

      if (((*ptr)->alignment - 1) & bytes)
	bytes = ALIGN (bytes, (*ptr)->alignment);
      if ((*ptr)->type == FFI_TYPE_STRUCT)
	{
	  if ((*ptr)->size > 8)
	    {
	      bytes += (*ptr)->size;
	      bytes += sizeof (void *);
	    }
	  else
	    {
	      if ((*ptr)->size > 4)
		bytes += 8;
	      else
		bytes += 4;
	    }
	}
      else
	bytes += STACK_ARG_SIZE ((*ptr)->size);
    }

  cif->bytes = bytes;

  return ffi_prep_cif_machdep (cif);
}

ffi_status
ffi_prep_cif_machdep (ffi_cif * cif)
{
  switch (cif->rtype->type)
    {
    case FFI_TYPE_VOID:
    case FFI_TYPE_STRUCT:
    case FFI_TYPE_FLOAT:
    case FFI_TYPE_DOUBLE:
    case FFI_TYPE_SINT64:
    case FFI_TYPE_UINT64:
      cif->flags = (unsigned) cif->rtype->type;
      break;

    default:
      cif->flags = FFI_TYPE_INT;
      break;
    }

  return FFI_OK;
}

extern void ffi_call_SYSV (int (*)(char *, extended_cif *),
			   extended_cif *,
			   unsigned, unsigned, unsigned *, void (*fn) ())
     __attribute__ ((__visibility__ ("hidden")));

void
ffi_call (ffi_cif * cif, void (*fn) (), void *rvalue, void **avalue)
{
  extended_cif ecif;

  ecif.cif = cif;
  ecif.avalue = avalue;

  if ((rvalue == NULL) && (cif->rtype->type == FFI_TYPE_STRUCT))
    {
      ecif.rvalue = alloca (cif->rtype->size);
    }
  else
    ecif.rvalue = rvalue;

  switch (cif->abi)
    {
    case FFI_SYSV:
      ffi_call_SYSV (ffi_prep_args, &ecif, cif->bytes,
		     cif->flags, ecif.rvalue, fn);
      break;
    default:
      FFI_ASSERT (0);
      break;
    }
}

/* Because the following variables are not exported outside libffi, we
   mark them hidden.  */

/* Assembly code for the jump stub.  */
extern const char ffi_cris_trampoline_template[]
 __attribute__ ((__visibility__ ("hidden")));

/* Offset into ffi_cris_trampoline_template of where to put the
   ffi_prep_closure_inner function.  */
extern const int ffi_cris_trampoline_fn_offset
 __attribute__ ((__visibility__ ("hidden")));

/* Offset into ffi_cris_trampoline_template of where to put the
   closure data.  */
extern const int ffi_cris_trampoline_closure_offset
 __attribute__ ((__visibility__ ("hidden")));

/* This function is sibling-called (jumped to) by the closure
   trampoline.  We get R10..R13 at PARAMS[0..3] and a copy of [SP] at
   PARAMS[4] to simplify handling of a straddling parameter.  A copy
   of R9 is at PARAMS[5] and SP at PARAMS[6].  These parameters are
   put at the appropriate place in CLOSURE which is then executed and
   the return value is passed back to the caller.  */

static unsigned long long
ffi_prep_closure_inner (void **params, ffi_closure* closure)
{
  char *register_args = (char *) params;
  void *struct_ret = params[5];
  char *stack_args = params[6];
  char *ptr = register_args;
  ffi_cif *cif = closure->cif;
  ffi_type **arg_types = cif->arg_types;

  /* Max room needed is number of arguments as 64-bit values.  */
  void **avalue = alloca (closure->cif->nargs * sizeof(void *));
  int i;
  int doing_regs;
  long long llret = 0;

  /* Find the address of each argument.  */
  for (i = 0, doing_regs = 1; i < cif->nargs; i++)
    {
      /* Types up to and including 8 bytes go by-value.  */
      if (arg_types[i]->size <= 4)
	{
	  avalue[i] = ptr;
	  ptr += 4;
	}
      else if (arg_types[i]->size <= 8)
	{
	  avalue[i] = ptr;
	  ptr += 8;
	}
      else
	{
	  FFI_ASSERT (arg_types[i]->type == FFI_TYPE_STRUCT);

	  /* Passed by-reference, so copy the pointer.  */
	  avalue[i] = *(void **) ptr;
	  ptr += 4;
	}

      /* If we've handled more arguments than fit in registers, start
	 looking at the those passed on the stack.  Step over the
	 first one if we had a straddling parameter.  */
      if (doing_regs && ptr >= register_args + 4*4)
	{
	  ptr = stack_args + ((ptr > register_args + 4*4) ? 4 : 0);
	  doing_regs = 0;
	}
    }

  /* Invoke the closure.  */
  (closure->fun) (cif,

		  cif->rtype->type == FFI_TYPE_STRUCT
		  /* The caller allocated space for the return
		     structure, and passed a pointer to this space in
		     R9.  */
		  ? struct_ret

		  /* We take advantage of being able to ignore that
		     the high part isn't set if the return value is
		     not in R10:R11, but in R10 only.  */
		  : (void *) &llret,

		  avalue, closure->user_data);

  return llret;
}

/* API function: Prepare the trampoline.  */

ffi_status
ffi_prep_closure (ffi_closure* closure,
		  ffi_cif* cif,
		  void (*fun)(ffi_cif *, void *, void **, void*),
		  void *user_data)
{
  void *innerfn = ffi_prep_closure_inner;
  FFI_ASSERT (cif->abi == FFI_SYSV);
  closure->cif  = cif;
  closure->user_data = user_data;
  closure->fun  = fun;
  memcpy (closure->tramp, ffi_cris_trampoline_template,
	  FFI_CRIS_TRAMPOLINE_CODE_PART_SIZE);
  memcpy (closure->tramp + ffi_cris_trampoline_fn_offset,
	  &innerfn, sizeof (void *));
  memcpy (closure->tramp + ffi_cris_trampoline_closure_offset,
	  &closure, sizeof (void *));

  return FFI_OK;
}